Device to be Charged, Wireless Charging Device and Control Method Thereof

ABSTRACT

The present disclosure provides a device to be charged, a wireless charging device and a control method thereof. The device to be charged includes: a wireless receiving circuit, configured to receive an electromagnetic signal transmitted by a wireless charging device and convert the electromagnetic signal to a first output voltage; a step-down circuit, configured to perform step-down process on the first output voltage to obtain a second output voltage, and charge a battery of the device to be charged based on the second output voltage; a temperature detecting circuit, configured to detect a temperature of the device to be charged; a communication control circuit, configured to send feedback information to the wireless charging device, when the temperature is larger than a preset threshold. The feedback information is configured to trigger the wireless charging device to control wireless charging process to reduce the first output voltage.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is a continuation of International Application No.PCT/CN2018/081963, filed on Apr. 4, 2018, which claims priority toInternational Application No. PCT/CN2017/079784, filed on Apr. 7, 2017,the entire contents of both of which are incorporated herein byreference in their entireties.

TECHNICAL FIELD

The present disclosure relates to a wireless charging field, and moreparticularly, to a device to be charged, a wireless charging device anda control method thereof.

BACKGROUND

At present, in the charging technology field, a device to be charged istypically charged in a wired charging mode.

Taking a mobile phone as an example, the mobile phone is typicallycharged in a wired charging mode. In detail, when there is a need tocharge the mobile phone, the mobile phone may be coupled with a powersupply device via a charging cable (for example, a USB (universal serialbus) cable), and an output power of the power supply device may betransmitted to the mobile phone via the charging cable, to charge abattery in the mobile phone.

For the device to be charged, it needs to use the charging cable in thewired charging mode, which results in cumbersome operation in a chargingpreparation stage. Thus, a wireless charging mode has been favored moreand more by people. However, the conventional wireless charging mode hasa bad effect, and needs improvement.

SUMMARY

In a first aspect, a device to be charged is provided. The device to becharged includes: a wireless receiving circuit, configured to receive anelectromagnetic signal transmitted by a wireless charging device andconvert the electromagnetic signal to an output voltage of the wirelessreceiving circuit; a step-down circuit, configured to receive the outputvoltage of the wireless receiving circuit, perform step-down process onthe output voltage of the wireless receiving circuit to obtain an outputvoltage of the step-down circuit, and charge a battery of the device tobe charged based on the output voltage of the step-down circuit; atemperature detecting circuit, configured to detect a temperature of thedevice to be charged; and a communication control circuit, configured tosend feedback information to the wireless charging device, when thetemperature of the device to be charged is larger than a presetthreshold, wherein the feedback information is configured to trigger thewireless charging device to control wireless charging process to reducethe output voltage of the wireless receiving circuit.

In a second aspect, a wireless charging device is provided. The wirelesscharging device includes: a wireless transmitting circuit, configured totransmit an electromagnetic signal to perform wireless charging on adevice to be charged; and a communication control circuit, configuredto: receive feedback information sent by the device to be charged when atemperature of the device to be charged is greater than a presetthreshold; and control the wireless charging according to the feedbackinformation to reduce an output voltage of a wireless receiving circuitof the device to be charged.

In a third aspect, a charging control method is provided. The method isapplied to a wireless charging device, and includes: transmitting anelectromagnetic signal to perform wireless charging on a device to becharged; receiving feedback information sent by the device to be chargedwhen a temperature of the device to be charged is greater than a presetthreshold; and controlling the wireless charging according to thefeedback information to reduce an output voltage of a wireless receivingcircuit of the device to be charged.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic diagram illustrating a conventional wirelesscharging system.

FIG. 2 is a schematic diagram of a wireless charging system according toan embodiment of the present disclosure.

FIG. 3 is a schematic diagram of a wireless charging system according toanother embodiment of the present disclosure.

FIG. 4 is a schematic diagram of a wireless charging system according toyet another embodiment of the present disclosure.

FIG. 5 is a schematic diagram of a wireless charging system according tostill another embodiment of the present disclosure.

FIG. 6 is a schematic diagram of a wireless charging system according tostill yet another embodiment of the present disclosure.

FIG. 7 is a schematic diagram of a device to be charged according to anembodiment of the present disclosure.

FIG. 8 is a schematic flowchart of a wireless charging method accordingto an embodiment of the present disclosure.

FIG. 9 is a schematic flowchart of a wireless charging method accordingto another embodiment of the present disclosure.

DETAILED DESCRIPTION

In embodiments of the present disclosure, a device to be charged ischarged based on a wireless charging technology, which can completepower transmission without a cable, simplifying operations in a chargingpreparation stage.

In the conventional wireless charging technology, a power supply device(for example, an adapter) is typically coupled with a wireless chargingdevice (for example, a wireless charging base), and an output power ofthe power supply device is transmitted to the device to be charged in awireless mode (for example, in a form of electromagnetic signal orelectromagnetic wave) via the wireless charging device, to performwireless charging on the device to be charged.

According to different wireless charging principles, the wirelesscharging mode can be implemented by magnetic coupling (orelectromagnetic induction), magnetic resonance, and radio waves. Atpresent, the mainstream wireless charging standards include a QIstandard, a PMA (power matters alliance) standard, and an A4WP (alliancefor wireless power). The QI standard and the PMA standard adopts themagnetic coupling for wireless charging. The A4WP standard adopts themagnetic resonance for wireless charging.

In the following, the conventional wireless charging mode is describedwith reference to FIG. 1.

As illustrated in FIG. 1, the wireless charging system includes a powersupply device 110, a wireless charging device 120 and a device to becharged 130. The wireless charging device 120 may be, for example, awireless charging base. The device to be charged 130 may be, forexample, a terminal.

After the power supply device 110 is coupled with the wireless chargingdevice 120, an output current of the power supply device 110 may betransmitted to the wireless charging device 120. The wireless chargingdevice 120 may convert the output current of the power supply device 110to an electromagnetic signal (or an electromagnetic wave) via aninternal wireless transmitting circuit 121 for transmitting. Forexample, the wireless transmitting circuit 121 may convert the outputcurrent of the power supply device to alternating current, and convertthe alternating current to the electromagnetic signal via a transmittingcoil or transmitting antenna (not shown).

The device to be charged 130 may receive the electromagnetic signaltransmitted by the wireless transmitting circuit 121 via the wirelessreceiving circuit 131, and convert the electromagnetic signal to anoutput current of the wireless receiving circuit 131. For example, thewireless receiving circuit 131 may convert the electromagnetic signaltransmitted by the wireless transmitting circuit 121 to alternatingcurrent via a receiving coil or receiving antenna (not shown), andperform operations such as rectification and/or filtering on thealternating current to convert the alternating current to an outputvoltage and an output current of the wireless receiving circuit 131.

For the conventional wireless charging technology, before the wirelesscharging, the wireless charging device 120 and the device to be charged130 may negotiate a transmitting power of the wireless transmittingcircuit 121 in advance. Assuming that the power negotiated by thewireless charging device 120 and the device to be charged 130 is 5 W,the output voltage and the output current of the wireless receivingcircuit 131 are generally 5V and 1 A. Assuming that the power negotiatedby the wireless charging device 120 and the device to be charged 130 is10.8 W, the output voltage and the output current of the wirelessreceiving circuit 131 are generally 9V and 1.2 A.

The output voltage of the wireless receiving circuit 131 is not suitablefor being directly applied to both ends of the battery 133, and needs tobe first converted by the conversion circuit 132 in the device to becharged 130, such that a charging voltage and/or a charging currentexpected by the battery 133 in the device to be charged 130 areobtained.

The conversion circuit 132 may be configured to convert the outputvoltage of the wireless receiving circuit 131 (for example, constantvoltage and/or constant current control), to meet a requirement of thecharging voltage and/or charging current expected by the battery 133.

As an example, the conversion circuit 132 may be a charging managementmodule, such as a charging integrated circuit (IC). During a chargingprocess of the battery 133, the conversion circuit 132 may be configuredto manage the charging voltage and/or charging current of the battery133. The conversion circuit 132 may have at least one of a voltagefeedback function and a current feedback function, so as to manage thecharging voltage and/or charging current of the battery 133.

For example, the charging process of the battery may include at leastone of a trickle charging stage, a constant current charging stage and aconstant voltage charging stage. In the trickle charging stage, theconversion circuit 132 may utilize a current feedback loop to ensurethat a current flowing into the battery 133 in the trickle chargingstage meets the charging current (such as a first charging current)expected by the battery 133. In the constant current charging stage, theconversion circuit 132 may utilize a current feedback loop to ensurethat the current flowing into the battery 133 in the constant currentcharging stage meets the charging current (such as a second chargingcurrent, which may be greater than the first charging current) expectedby the battery 133. In the constant voltage charging stage, theconversion circuit 132 may utilize a voltage feedback loop to ensurethat a voltage applied to both ends of the battery 133 in the constantvoltage charging stage meets the charging voltage expected by thebattery 133.

As an example, when the output voltage of the wireless receiving circuit131 is greater than the charging voltage expected by the battery 133,the conversion circuit 132 may be configured to perform a buckconversion on the output voltage of the wireless receiving circuit 131to enable a buck-converted charging voltage to meet the requirement ofthe charging voltage expected by the battery 133. As another example,when the output voltage of the wireless receiving circuit 131 is lessthan the charging voltage expected by the battery 133, the conversioncircuit 132 may be configured to perform a boost conversion on theoutput voltage of the wireless receiving circuit 132 to enable aboost-converted charging voltage to meet the requirement of the chargingvoltage expected by the battery 133.

As another example, assume that the wireless receiving circuit 131outputs a constant voltage of 5V. When the battery 133 includes a singlebattery cell (such as a lithium battery cell, a charging cut-off voltageof a single battery cell is typically 4.2V), the conversion circuit 132(for example, a buck circuit) may perform a buck conversion on theoutput voltage of the wireless receiving circuit 131, such that thecharging voltage obtained after the buck conversion meets a requirementof the charging voltage expected by the battery 133.

As yet another example, assume that the wireless receiving circuit 131outputs a constant voltage of 5V. When the battery 133 includes two ormore battery cells (such as lithium battery cell, a charging cut-offvoltage of a single battery cell is typically 4.2V) coupled in series,the conversion circuit 132 (for example, a boost circuit) may perform aboost conversion on the output voltage of the wireless receiving circuit131, such that the charging voltage obtained after the boost conversionmeets a requirement of the charging voltage expected by the battery 133.

Limited by a poor conversion efficiency of the conversion circuit 132, apart of electric energy is lost in a form of heat, and the heat maygather inside the device to be charged 130. A design space and a spacefor heat dissipation of the device to be charged are small (for example,the physical size of a mobile terminal used by a user becomes thinnerand thinner, while plenty of electronic elements are densely arranged inthe mobile terminal to improve performance of the mobile terminal),which not only increases difficulty in designing the conversion circuit132, but also results in that it is hard to dissipate the heat gatheredin the device to be charged 130 in time, thus further causing anabnormity of the device to be charged 130.

For example, the heat gathered on the conversion circuit 132 may cause athermal interference on electronic elements neighboring the conversioncircuit 132, thus causing abnormal operations of the electronicelements. For another example, the heat gathered on the conversioncircuit 132 may shorten the service life of the conversion circuit 132and neighboring electronic elements. For yet another example, the heatgathered on the conversion circuit 132 may cause a thermal interferenceon the battery 133, thus causing abnormal charging and/or abnormaldischarging of the battery 133. For still another example, the heatgathered on the conversion circuit 132 may increase the temperature ofthe device to be charged 130, thus affecting user experience during thecharging. For still yet another example, the heat gathered on theconversion circuit 132 may short-circuit the conversion circuit 132,such that the output voltage of the wireless receiving circuit 131 isdirectly applied to both ends of the battery 133, thus causing abnormalcharging of the battery 133, which brings safety hazard if theover-voltage charging lasts for a long time, for example, the battery133 may explode.

In order to solve the above problem, embodiments of the presentdisclosure provide a wireless charging system. The wireless chargingdevice and the device to be charged in the wireless charging system canperform wireless communication, such that the wireless charging devicecan control the wireless charging process, to enable the transmittingpower of the wireless charging device to match the charging voltageand/or charging current presently required by the battery in the deviceto be charged (or matches a present charging phase of the battery in thedevice to be charged). The transmitting power of the wireless chargingdevice matching the charging voltage and/or the charging currentpresently required by the battery refers to that the transmitting powerof the electromagnetic signal is configured by the wireless chargingdevice such that, after the electromagnetic signal is received by thewireless receiving circuit, the output voltage and/or the output currentof the wireless receiving circuit match the charging voltage and/orcharging current presently required by the battery in the device to becharged (or the output voltage and/or output current of the wirelessreceiving circuit meet the charging requirement of the battery in thedevice to be charged). In this way, in the device to be charged, theoutput voltage and/or the output current of the wireless receivingcircuit can be directly applied to both ends of the battery to chargethe battery (hereinafter, this charging method of the device to becharged is referred to as direct charging) , thus avoiding theabove-mentioned problems such as energy loss and heating caused by theconversion circuit converting the output voltage and/or the outputcurrent of the wireless receiving circuit.

After solving the heating problem of the conversion circuit, the mainheat sources in the wireless charging process are concentrated in thewireless transmitting circuit (including the transmitting coil) and thewireless receiving circuit (including the receiving coil).

Assuming that the charging power is 20 W, and the chargingvoltage/charging current of a single cell is 5V/4 A. As a possibleimplementation, the wireless transmitting circuit can generate anelectromagnetic signal based on 5V/4 A, and accordingly, the wirelessreceiving circuit converts the electromagnetic signal into an outputvoltage/output current of 5V/4 A. This charging method based on lowvoltage and high current will cause the wireless transmitting circuitand the wireless receiving circuit to generate a large amount of heatduring the power transmission process.

In order to reduce the heat generation of the wireless transmittingcircuit and the wireless receiving circuit, embodiments of the presentdisclosure further improve the above direct charging mode, and provide astep-down circuit between the wireless receiving circuit and thebattery, and uses the output voltage of the step-down circuit as thecharging voltage of the battery. Assuming that the charging power is 20W, and the charging voltage/charging current of a single cell is 5V/4 A,in order to meet the requirement of the battery on the charging voltage,the output voltage/output current of the step-down circuit needs to bemaintained at 5V/4 A. Assuming that the step-down circuit is ahalf-voltage circuit, the voltage before the step-down is 10V/2 A. Inthis way, the wireless transmitting circuit generates an electromagneticsignal based on 10V/2 A, and accordingly, the wireless receiving circuitconverts the electromagnetic signal into an output voltage/outputcurrent of 10V/2 A, and the heat generated in the power transmissionprocess is reduced accordingly due to the current being reduced from 4Ato 2 A.

In the following, the wireless charging system 200 provided by anembodiment of the present disclosure is described in detail withreference to FIG. 2.

As illustrated in FIG. 2, the wireless charging system provided by anembodiment of the present disclosure may include a wireless chargingdevice 220 and a device to be charged 230.

The wireless charging device 220 may include a wireless transmittingcircuit 221 and a communication control circuit 222. Control functionsof the communication control circuit 222 may be implemented, forexample, by a MCU (micro control unit).

The wireless transmitting circuit 221 may be configured to transmit anelectromagnetic signal, to perform wireless charging on the device to becharged 230. In some embodiments, the wireless transmitting circuit 221may include a wireless transmitter drive circuit and a transmitting coilor a transmitting antenna (not shown in drawings). The wirelesstransmitter drive circuit may be configured to generate an alternatingcurrent with a higher frequency. The transmitting coil or transmittingantenna may be configured to convert the alternating current with thehigher frequency to the electromagnetic signal for transmission.

The communication control circuit 222 may be configured to performwireless communication with the device to be charged 230 during thewireless charging. In detail, the communication control circuit 222 maycommunicate with a communication control circuit 236 in the device to becharged 230. In embodiments of the present disclosure, a communicationmode between the communication control circuit 222 and the communicationcontrol circuit 236 and communication information between thecommunication control circuit 222 and the communication control circuit236 are not limited, and will be described in detail below withreference to specific embodiments.

The device to be charged 230 may include a wireless receiving circuit231, a battery 232, a step-down circuit 234, a temperature detectingcircuit 235 and the communication control circuit 236. Control functionsof the communication control circuit 236 may be implemented, forexample, by a MCU (micro control unit), or may be implemented by the MCUtogether with an application processor in the device to be charged.

The wireless receiving circuit 231 may be configured to receive theelectromagnetic signal, and to convert the electromagnetic signal to anoutput current and an output voltage of the wireless receiving circuit231. In detail, the wireless receiving circuit 231 may include areceiving coil or receiving antenna (not shown), and a shaping circuit,such as a rectification circuit and/or a filtering circuit, coupled withthe receiving coil or receiving antenna. The receiving coil or receivingantenna may be configured to convert the electromagnetic signal toalternating current. The shaping circuit may be configured to convertthe alternating current to the output voltage and the output current ofthe wireless receiving circuit 231.

It should be noted that, in embodiments of the present disclosure,specific forms of the shaping circuit and forms of the output currentand the output voltage of the wireless receiving circuit 231 obtainedafter shaping of the shaping circuit are not limited.

In some embodiments, the shaping circuit may include the rectificationcircuit and the filtering circuit, and the output voltage of thewireless receiving circuit 231 may be a stable voltage obtained afterfiltering. In other embodiments, the shaping circuit may include therectification circuit, and the output voltage of the wireless receivingcircuit 231 may be a voltage with a pulsating waveform obtained afterrectification, in which the voltage with the pulsating waveform isdirectly applied to both ends of the battery 232 in the device to becharged 230 for charging the battery 232. There are many ways to adjustthe output voltage of the wireless receiving circuit 231 to the voltagewith the pulsating waveform, for example, by removing the filteringcircuit in the wireless receiving circuit 231, and only remaining therectification circuit.

It could be understood that, the output current of the wirelessreceiving circuit 231 may charge the battery 232 intermittently, and aperiod of the output current of the wireless receiving circuit 231 mayvary with a frequency of the alternating current input into the wirelesscharging system 200 (for example, a frequency of the alternating currentpower grid). For example, a frequency corresponding to the period of theoutput current of the wireless receiving circuit 231 may be an integralmultiple or a reciprocal multiple of the frequency of the power grid.Moreover, when the output current of the wireless receiving circuit 231may charge the battery 232 intermittently, the current waveformcorresponding to the output current of the wireless receiving circuit231 may consist of one pulse or a set of pulses synchronous with thepower grid. A magnitude of the voltage/current with the pulsatingwaveform changes periodically, which, compared to the conventionalconstant direct current, may reduce lithium precipitation of a lithiumbattery, and prolong a service life of the battery, and moreover may bebeneficial to reduce polarization effect of the battery, improve acharging speed, and reduce heating of the battery, thus ensuring safetyand reliability of charging the device to be charged.

The step-down circuit 234 may be configured to receive the outputvoltage of the wireless receiving circuit 231, perform a step-downprocess on the output voltage of the wireless receiving circuit 231 toobtain an output voltage and an output current of the step-down circuit234, and charge the battery 232 based on the output voltage and outputcurrent of the step-down circuit 234.

The implementations of the step-down circuit 234 may be various. As anexample, the step-down circuit 234 may be a Buck circuit. As anotherexample, the step-down circuit 234 may be a charge pump.

The introduction of the step-down circuit 234 makes the voltagegenerated during the wireless transmission (e.g., the output voltage ofthe wireless receiving circuit) keep at a higher voltage, therebyfurther reducing the heat generation of the system.

The smaller the voltage difference between the input voltage and theoutput voltage of the step-down circuit 234 is, the higher the workingefficiency of the step-down circuit 234 is, and the smaller the quantityof heat generation is. Accordingly, the larger the voltage differencebetween the input voltage and the output voltage of the step-downcircuit 234 is, the lower the working efficiency of the step-downcircuit 234 is, and the larger the quantity of heat generation is.Therefore, for the step-down circuit 234 with lower efficiency, moreheat is generated during the step-down process.

Based on the above considerations, in embodiments of the presentdisclosure, a temperature detecting circuit 235 is provided. Thecommunication control circuit 236 detects the temperature of the deviceto be charged 230 based on the temperature detecting circuit 235, toform a wireless charging system with a temperature feedback mechanism,which can monitor the temperature of the device to be charged 230, andincrease the working efficiency of the step-down circuit 234 in timewhen the temperature of the device to be charged 230 is greater than acertain threshold, thereby reducing the heat generation of the system.

The temperature monitoring mechanism of the temperature detectingcircuit 235 and the communication control circuit 236 will be describedin detail below with reference to FIG. 2.

The temperature detecting circuit 235 may be configured to detect thetemperature of the device to be charged 230. The temperature detectingcircuit 235 may be implemented in various forms. For example, thetemperature detecting circuit 235 may include a temperature detectingresistor. The temperature detecting resistor may be, for example, athermistor. The temperature detecting circuit 235 may determine thetemperature of the device to be charged 230 based on a resistance valueof the thermistor.

The position of the temperature detecting circuit 235 in the device tobe charged 230 is not specifically limited in embodiments of the presentdisclosure. As an example, the temperature detecting circuit 235 may bedisposed near a heat source inside the device to be charged 230. Forexample, the temperature detecting resistor in the temperature detectingcircuit 235 may be disposed in the vicinity of the step-down circuit234. Assuming that the step-down circuit 234 is a BUCK IC, thetemperature detecting resistor may be added to the BUCK IC. In thiscase, the temperature of the device to be charged 230 may also beunderstood as the temperature of the step-down circuit 234, that is, thetemperature of the step-down circuit 234 is regarded as the temperatureof the device to be charged 230.

The communication control circuit 236 may be configured to send feedbackinformation to the wireless charging device 220, when the temperature ofthe device to be charged 230 is greater than a preset threshold. Thefeedback information is configured to trigger the wireless chargingdevice 220 to control the wireless charging process, to reduce theoutput voltage of the wireless receiving circuit 231 (“reducing theoutput voltage of the wireless receiving circuit 231” herein may bereplaced by “reducing the difference between the input voltage and theoutput voltage of the step-down circuit 234”; or, replaced by“increasing the working efficiency of the step-down circuit 234”).

It should be noted that during the wireless charging process, therequirement for the charging voltage and the charging current of thebattery 232 is generally determined by the charging phase in which thebattery 232 is presently located. Since the charging voltage and thecharging current of the battery 232 are the output voltage and outputcurrent of the step-down circuit 234, the output voltage and outputcurrent of the step-down circuit 234 are also determined by the chargingphase in which the battery 232 is presently located. In order toincrease the working efficiency of the step-down circuit 234, it isnecessary to reduce the voltage difference between the input voltage andthe output voltage of the step-down circuit 234. Since the outputvoltage of the step-down circuit 234 depends on the charging phase inwhich the battery 232 is presently located, it cannot be adjustedarbitrarily. Therefore, in order to reduce the voltage differencebetween the input voltage and the output voltage of the step-downcircuit 234, the input voltage of the step-down circuit 234 may bereduced, that is, the output voltage of the wireless receiving circuit231 may be reduced (in embodiments of the present disclosure, the outputvoltage of the wireless receiving circuit 231 and the input voltage ofthe step-down circuit 234 are the same voltage).

Therefore, in embodiments of the present disclosure, when thetemperature of the device to be charged 230 is greater than the presetthreshold, the feedback information is sent to the wireless chargingdevice 220 through the communication control circuit 236, such that thewireless charging device 220 is triggered to control the wirelesscharging process to reduce the output voltage of the wireless receivingcircuit 231.

The wireless charging device 220 may reduce the output voltage of thewireless receiving circuit 231 in various manners according to thefeedback information.

As an example, the wireless charging device 220 may reduce a duty ratioof the wireless transmitting circuit 221 according to the feedbackinformation, to reduce the output voltage of the wireless receivingcircuit 231.

As another example, the wireless charging device 220 may adjust atransmitting frequency of the wireless transmitting circuit 221according to the feedback information, to reduce the output voltage ofthe wireless receiving circuit 231.

As still another example, the wireless charging device 220 may reducethe output voltage of the voltage conversion circuit 224 to reduce theoutput voltage of the wireless receiving circuit 231. A detaileddescription of the structure and function of the voltage conversioncircuit 224 will be described later with reference to FIGS. 5-6.

It should be noted that the wireless charging device 220 may reduce theoutput voltage of the wireless receiving circuit 231 by using a certainmethod described above, or may reduce the output voltage of the wirelessreceiving circuit 231 by using a combination of above methods. Forexample, the wireless charging device 220 may achieve the purpose ofreducing the output voltage of the wireless receiving circuit 231 onlyby reducing the output voltage of the voltage conversion circuit 224.For another example, the wireless charging device 220 may first roughlyadjust the output voltage of the wireless receiving circuit 231 (or theworking efficiency of the step-down circuit 234) by reducing the outputvoltage of the voltage conversion circuit 224, and then finely adjustthe output voltage of the wireless receiving circuit 231 (or the workingefficiency of the step-down circuit 234) by adjusting the duty ratioand/or the transmitting frequency of the wireless transmitting circuit.

The specific content of the feedback information is not specificallylimited in embodiments of the present disclosure. For example, thefeedback information may be information indicating the temperature ofthe device to be charged 230. For another example, the feedbackinformation may be information indicating that the temperature of thedevice to be charged 230 is too high. For example, when the wirelesscharging device 220 reduces the output voltage of the wireless receivingcircuit 231 by reducing the output voltage of the voltage conversioncircuit 224, the feedback information may be information indicating thatthe output voltage of the voltage conversion circuit 224 is too high.For example, when the wireless charging device 220 reduces the outputvoltage of the wireless receiving circuit 231 by adjusting thetransmitting frequency and/or the duty ratio of the wirelesstransmitting circuit 221, the feedback information may be informationindicating that the transmitting frequency and/or the duty ratio of thewireless transmitting circuit 221 is too high.

In some embodiments, the communication control circuit 236 may befurther configured to perform wireless communication with thecommunication control circuit 222, such that the communication controlcircuit 222 controls the wireless charging process, to enable the outputvoltage and/or output current of the step-down circuit 234 to match thecharging voltage and/or charging current presently required by thebattery 232.

In other words, the communication control circuit 236 may be configuredto perform wireless communication with the communication control circuit222, such that the communication control circuit 222 controls thewireless charging process, to enable the output voltage and/or outputcurrent of the step-down circuit 234 to satisfy the chargingrequirements of the battery 232 in at least one of a trickle chargingphase, a constant voltage charging phase, and a constant currentcharging phase.

The communication control circuit 236 may obtain the output voltageand/or the output current of the step-down circuit 234 through a certaindetection circuit (such as a voltage detection circuit and/or a currentdetection circuit) or a certain detection mode, and may perform wirelesscommunication with the communication control circuit 222 based on theoutput voltage and/or the output current of the step-down circuit 234.

The device to be charged used in embodiments of the present disclosuremay refer to the “terminal”. The “terminal” may include, but is notlimited to a device configured to receive/transmit communication signalsvia a wired connection (for example, public switched telephone network(PSTN), digital subscriber line (DSL) connection, digital cableconnection, direct cable connection and/or another dataconnection/network) and/or via a wireless interface (for example,cellular network, wireless local area network (WLAN), digital TV networksuch as digital video broadcasting handheld (DVB-H) network, satellitenetwork, an amplitude modulation-frequency modulation (AM-FM)broadcasting transmitter, and/or a wireless interface of anothercommunication terminal). The communication terminal configured tocommunicate via the wireless interface may be referred to as “wirelesscommunication terminal”, “wireless terminal” and/or “mobile terminal”.Examples of a mobile terminal include, but are not limited to asatellite phone or a cell phone, a terminal combining a cell radio phoneand a personal communication system (PCS) having capability of dataprocess, fax, and data communication, a personal digital assistant (PDA)including a radio phone, a pager, Internet/Intranet access, a webbrowser, a note pad & address book, a calendar and/or a globalpositioning system (GPS) receiver, and a common laptop and/or handheldreceiver, or other electronic devices including a radio phonetransceiver. In addition, the device to be charged or terminal used inembodiments of the present disclosure may further include a power bank.The power bank may receive charging from the wireless charging device,and store the energy, for providing power for other electronic devices.

The communication mode and the communication sequence between thewireless charging device 220 and the device to be charged 230 are notlimited in embodiments of the present disclosure.

In some embodiments, the wireless communication between the wirelesscharging device 220 and the device to be charged 230 (or, between thecommunication control circuit 236 and the communication control circuit222) may be a unidirectional wireless communication. For example, duringthe wireless charging of the battery 232, the device to be charged 230may be an initiator of the communication, and the wireless chargingdevice 220 may be a receiver of the communication. For example, duringthe constant current charging stage of the battery, the device to becharged 230 may detect the charging current of the battery 232 (i.e.,the output current of the wireless receiving circuit 231) in real time,and when the charging current of the battery 232 does not match thecharging current presently required by the battery, the device to becharged 230 sends an adjustment message to the wireless charging device220, to instruct the wireless charging device 220 to adjust thetransmitting power of the wireless transmitting circuit 221.

In some embodiments, the wireless communication between the wirelesscharging device 220 and the device to be charged 230 (or, between thecommunication control circuit 236 and the communication control circuit222) may be a bidirectional wireless communication. The bidirectionalwireless communication generally requires that, the receiver sends aresponse message to the initiator after receiving the communicationrequest initiated by the initiator. The bidirectional communicationscheme may enable the communication to be safer.

The master-slave relation of the wireless charging device 220 (thecommunication control circuit 222 in the wireless charging device 220)and the device to be charged 230 (the communication control circuit 236in the device to be charged 230) is not limited by above description ofembodiments of the present disclosure. In other words, any of thewireless charging device 220 and the device to be charged 230 can beconfigured as the master device for initiating the bidirectionalcommunication session, accordingly, the other one can be configured asthe slave device for making a first response or a first reply to thecommunication initiated by the master device. As a feasibleimplementation, during the communication, the identities of the masterdevice and the slave device can be determined by comparing the linkstates between the wireless charging device 220 and the device to becharged 230. For example, assume that the wireless link of sendingmessages from the wireless charging device 220 to the device to becharged 230 is the uplink, and the wireless link of sending messagesfrom the device to be charged 230 to the wireless charging device is thedownlink. If the link quality of the uplink is better, the wirelesscharging device 220 may be configured as the master device of thecommunication. If the link quality of the downlink is better, the deviceto be charged 230 may be configured as the master device of thecommunication.

The specific implementation of bidirectional communication between thewireless charging device 220 and the device to be charged 230 is notlimited in embodiments of the present disclosure. In other words, any ofthe wireless charging device 220 and the device to be charged 230 can beconfigured as the master device for initiating the bidirectionalcommunication session, accordingly, the other one can be configured asthe slave device making a first response or a first reply to thecommunication initiated by the master device, and the master device isable to make a second response to the first response or the first replyof the slave device, and thus one negotiation process is completedbetween the master device and the slave device.

As an implementation, the mater device is able to make a second responseto the first response or the first reply made by the slave device withrespect to the communication session in a manner that, the master deviceis able to receive the first response or the first reply made by theslave device with respect to the communication session and to make atargeted second response to the first response or the first reply.

As another implementation, the mater device is able to make a secondresponse to the first response or the first reply made by the slavedevice with respect to the communication session in a manner that, whenthe master device does not receive the first response or the first replymade by the slave device with respect to the communication session inthe predetermined time period, the mater device also makes the targetedsecond response to the first response or the first reply of the slavedevice.

In some embodiments, when the device to be charged 230 is configured asthe mater device for initiating the communication session, after thewireless charging device 220 configured as the slave device makes thefirst response or the first reply to the communication session initiatedby the master device, it is unnecessary for the device to be charged 230to make the targeted second response to the first response or the firstreply of the wireless charging device 220, i.e., one negotiation processis regarded as completed between the wireless charging device 220 andthe device to be charged 230.

In embodiments of the present disclosure, the wireless communicationmode between the communication control circuit 222 of the wirelesscharging device 220 and the communication control circuit 236 of thedevice to be charged 230 is not limited. For example, the communicationcontrol circuit 222 and the communication control circuit 236 mayperform the wireless communication based on Bluetooth, Wi-Fi (wirelessfidelity) or backscatter modulation (or power load modulation).

In embodiments of the present disclosure, communication content betweenthe communication control circuit 236 and the communication controlcircuit 222 is not limited. Besides the feedback information related tothe temperature, other communication information may be included, whichwill be described in detail below with reference to detailedembodiments.

As an example, the communication control circuit 236 may send the outputvoltage and/or the output current of the step-down circuit 234 to thecommunication control circuit 222. Further, the communication controlcircuit 236 may further send battery status information to thecommunication control circuit 222, in which the battery statusinformation includes a present electric quantity and/or a presentvoltage of the battery 232 in the device to be charged 230. Thecommunication control circuit 222 may first determine the charging stagewhere the battery 232 is presently is according to the battery statusinformation, and further determine a target charging voltage and/or atarget charging current matching the charging voltage and/or thecharging current presently required by the battery 232. Next, thecommunication control circuit 222 may compare the output voltage and/orthe output current of the step-down circuit 234 sent from thecommunication control circuit 236 with the target charging voltageand/or the target charging current, to determine whether the outputvoltage and/or the output current of the step-down circuit 234 match thecharging voltage and/or the charging current presently required by thebattery 232. When the output voltage and/or the output current of thestep-down circuit 234 does not match the charging voltage and/or thecharging current presently required by the battery 232, the transmittingpower of the wireless transmitting circuit 221 is adjusted, until theoutput voltage and/or the output current of the step-down circuit 234match the charging voltage and/or the charging current presentlyrequired by the battery 232.

As another example, the communication control circuit 236 may send theadjustment message to the communication control circuit 222, to instructthe communication control circuit 222 to adjust the transmitting powerof the wireless transmitting circuit 221. For example, the communicationcontrol circuit 236 may instruct the communication control circuit 222to increase the transmitting power of the wireless transmitting circuit221. For another example, the communication control circuit 236 mayinstruct the communication control circuit 222 to decrease thetransmitting power of the wireless transmitting circuit 221. In moredetail, the wireless charging device 220 may set a plurality of levelsfor the transmitting power of the wireless transmitting circuit 221.Every time when the communication control circuit 222 receives theadjustment message, it adjusts the transmitting power of the wirelesstransmitting circuit 221 by one level until the output voltage and/orthe output current of the step-down circuit 234 match the chargingvoltage and/or the charging current presently required by the battery232.

Besides the above communication contents, many other communicationinformation may be communicated between the communication controlcircuit 222 and the communication control circuit 236. In someembodiments, information used for safety protection, abnormalitydetection or failure processing, for example, temperature information ofthe battery 232, information indicating entering overvoltage protectionor overcurrent protection, and power transmission efficiency information(the power transmission efficiency information may be configured toindicate a power transmission efficiency between the wirelesstransmitting circuit 221 and the wireless receiving circuit 231), may becommunicated between the communication control circuit 222 and thecommunication control circuit 236.

For example, when the temperature of the battery 232 is too high, thecommunication control circuit 222 and/or the communication controlcircuit 236 may control the charging loop to enter a protection stage,for example, control the charging loop to stop the wireless charging.For another example, after the communication control circuit 222receives the information indicating the overvoltage protection or theovercurrent protection sent by the communication control circuit 236,the communication control circuit 222 may reduce the transmitting power,or control the wireless transmitting circuit 221 to stop working. Foranother example, after the communication control circuit 222 receivesthe power transmission efficiency information sent by the communicationcontrol circuit 236, the communication control circuit 222 may controlthe wireless transmitting circuit 221 to stop working if the powertransmission efficiency is lower than a preset threshold, and inform theuser of this matter, for example, may display via the display screenthat the power transmission efficiency is too low, or may indicate viaan indicator light that the power transmission efficiency is too low,such that the user may adjust the environment of the wireless charging.

In some embodiments, other information that can be used to adjust thetransmitting power of the wireless transmitting circuit 221, forexample, the temperature information of the battery, the informationindicating a peak value or a mean value of the output voltage and/or theoutput current of the step-down circuit 234, and the power transmissionefficiency information (the power transmission efficiency informationmay be configured to indicate the power transmission efficiency betweenthe wireless transmitting circuit 221 and the wireless receiving circuit231), may be communicated between the communication control circuit 222and the communication control circuit 236.

For example, the communication control circuit 236 may send the powertransmission efficiency information to the communication control circuit222, and the communication control circuit is further configured todetermine an adjustment magnitude of the transmitting power of thewireless transmitting circuit 221 according to the power transmissionefficiency information. In detail, if the power transmission efficiencyinformation indicates that the power transmission efficiency between thewireless transmitting circuit 221 and the wireless receiving circuit 231is low, the communication control circuit 222 may increase theadjustment magnitude of the transmitting power of the wirelesstransmitting circuit 221, such that the transmitting power of thewireless transmitting circuit 221 may reach the target power faster.

For another example, when the wireless receiving circuit 231 outputs thevoltage and/or the current with the pulsating waveform, thecommunication control circuit 236 may send the information indicatingthe peak value or the mean value of the output voltage and/or the outputcurrent of the step-down circuit 234 to the communication controlcircuit 222, and the communication control circuit 222 may determinewhether the peak value or the mean value of the output voltage and/orthe output current of the step-down circuit 234 matches the chargingvoltage and/or the charging current presently required by the battery,and if not, may adjust the transmitting power of the wirelesstransmitting circuit 221.

For another example, the communication control circuit 236 may send thetemperature information of the battery 232 to the communication controlcircuit 222, and if the temperature of the battery 232 is too high, thecommunication control circuit 222 may reduce the transmitting power ofthe wireless transmitting circuit 221, to reduce the output current ofthe wireless receiving circuit 231, thus reducing the temperature of thebattery 232.

The battery 232 in the wireless charging device 220 provided by theembodiments of the present disclosure may include a single cell, and mayalso include N cells (N is a positive integer greater than 1) connectedin series with each other. Taking N=2 as an example, as illustrated inFIG. 3, the battery 232 may include a cell 232 a and a cell 232 b, andthe cell 232 a and the cell 232 b are connected in series with eachother. Assuming that the charging power is 20 W, and the chargingvoltage of a single cell is 5V, in order to meet the charging voltagerequirements of the serial double cells, the output voltage/outputcurrent of the step-down circuit 234 needs to be maintained at 10V/2 A.In this case, the wireless transmitting circuit generateselectromagnetic signals based on 10V/2 A, and accordingly, the wirelessreceiving circuit converts the electromagnetic signals into an outputvoltage/output current of 10V/2 A, and the heat generated in the powertransmission process is reduced accordingly due to the current beingreduced from 4 A to 2 A. FIG. 3 is an example in which N=2, butactually, the value of N may be 3 or a positive integer of 3 or more.The more cells are connected in series, the smaller the amount of heatgenerated by the electric energy passing through the wirelesstransmitting circuit 221 and the wireless receiving circuit 231.

In some embodiments, the device to be charged includes the step-downcircuit 234 as illustrated in FIG. 2, and the battery 232 of the deviceto be charged 230 includes N cells (N is a positive integer greaterthan 1) connected in series with each other. Assuming that the chargingpower is 20 W, and the charging voltage of a single cell is equal to 5V,in order to meet the charging voltage requirements of the series doublecells, the output voltage/output current of the step-down circuit 234needs to be maintained at 10V/2 A. Assuming that the step-down circuit234 is a half-voltage circuit, the voltage before the step-down processis 20V/1 A. In this way, the wireless transmitting circuit generateselectromagnetic signals based on 20V/1 A, and accordingly, the wirelessreceiving circuit converts the electromagnetic signals into an outputvoltage/output current of 20V/1 A, which further reduces the heatgenerated in the power transmission process due to the current beingreduced from 4 A to 1 A.

As noted above, in embodiments of the present disclosure, the wirelesscharging device 220 can adjust the transmitting power of the wirelesstransmitting circuit 221 constantly during the charging process, suchthat the output voltage and/or the output current of the step-downcircuit 234 match the charging voltage and/or the charging currentpresently required by the battery 232. In embodiments of the presentdisclosure, the way of adjusting the transmitting power of the wirelesstransmitting circuit is not limited. For example, the communicationcontrol circuit 222 may communicate with the power supply device 210 toadjust the output current and/or the output voltage of the power supplydevice 210, so as to adjust the transmitting power of the wirelesstransmitting circuit 221. As another example, the communication controlcircuit 222 may adjust a power quantity drawn by the wirelesstransmitting circuit 221 from the maximum output power supplied by thepower supply device 210, so as to adjust the transmitting power of thewireless transmitting circuit 221. As another example, the wirelesscharging device 220 may directly receive alternating current (forexample, 220V alternating current), and the communication controlcircuit 222 may directly convert the alternating current to the requiredvoltage and/or current according to feedback from the communicationcontrol circuit 236. In the following, the way of adjusting thetransmitting power of the wireless transmitting circuit 221 is describedin detail with reference to FIGS. 4-6.

FIG. 4 is an example of a method of adjusting the transmitting power ofthe wireless transmitting circuit 221. As illustrated in FIG. 4, thewireless charging device 220 may further include a charging interface223. The charging interface 223 may be configured to couple to anexternal power supply device 210. The wireless transmitting circuit 221may be further configured to generate the electromagnetic signalaccording to the output voltage and the output current of the powersupply device 210. The communication control circuit 222 may be furtherconfigured to communicate with the power supply device 210 to negotiatethe maximum output power of the power supply device 210, and adjust thepower quantity drawn by the wireless transmitting circuit 221 from themaximum output power during the wireless charging, to adjust thetransmitting power of the wireless transmitting circuit 221.

In embodiments of the present disclosure, the communication controlcircuit 222 communicates with the power supply device 210 having theadjustable output power, to negotiate the maximum output power of thepower supply device 210. After the negotiation, the power supply device210 may provide the output voltage and the output current to thewireless charging device 220 according to the maximum output power.During the charging, the communication control circuit 222 may draw acertain power quantity from the maximum output power for wirelesscharging. In other words, in embodiments of the present disclosure,adjusting the transmitting power of the wireless transmitting circuit221 is controlled by the communication control circuit 222, which mayadjust the transmitting power of the wireless transmitting circuit 221immediately after receiving the feedback information of the device to becharged 230, having advantages of fast adjustment speed and highefficiency.

In embodiments of the present disclosure, the way in which thecommunication control circuit 222 draws the power quantity from themaximum output power provided by the power supply device 210 is notlimited. For example, the voltage conversion circuit (for example, maybe the power adjustment circuit) may be arranged inside the wirelesscharging device 220. The voltage conversion circuit may be coupled withthe transmitting coil or transmitting antenna, for adjusting the powerreceived by the transmitting coil or transmitting antenna. The voltageconversion circuit may include, for example, a PWM (pulse widthmodulation) controller and a switch unit. The communication controlcircuit 222 may adjust the transmitting power of the wirelesstransmitting circuit 221 by adjusting a duty ratio of a control signalsent by the PWM controller, and/or by controlling a switch frequency ofthe switch unit.

It should be noted that, in an embodiment as illustrated in FIG. 4, asan alternative implementation, the power supply device 210 may have thefixed and higher output power (for example, 40 W). In this way, thecommunication control circuit 222 may not need to negotiate with thepower supply device 210 about the maximum output power of the powersupply device 210, and may directly adjust the power quantity drawn bythe wireless transmitting circuit 221 from the fixed power supplied bythe power supply device 210.

In embodiments of the present disclosure, a type of the power supplydevice 210 is not limited. For example, the power supply device 210 maybe an adapter, a power bank, a car charger, a computer or the like.

In embodiments of the present disclosure, a type of the charginginterface 223 is not limited. In some embodiments, the charginginterface 223 may be a USB interface. The USB interface may be, forexample, a USB 2.0 interface, a micro USB interface, or a USB TYPE-Cinterface. In other embodiments, the charging interface 223 may also bea lightning interface, or any other kind of parallel interface and/orserial interface that can be used for charging.

In embodiments of the present disclosure, a communication mode betweenthe communication control circuit 222 and the power supply device 210 isnot limited. As an example, the communication control circuit 222 may becoupled with the power supply device 210 via a communication interfaceother than the charging interface, and may communicate with the powersupply device 210 via the communication interface. As another example,the communication control circuit 222 may communicate with the powersupply device 210 in a wireless mode. For example, the communicationcontrol circuit 222 may communicate with the power supply device 210 viaNFC (near field communication). As yet another example, thecommunication control circuit 222 may communicate with the power supplydevice 210 via the charging interface, without the need of arranging anadditional communication interface or other wireless communicationmodes, such that an implementation of the wireless charging device 220may be simplified. For example, the charging interface 223 is the USBinterface, and the communication control circuit 222 may communicatewith the power supply device 210 based on a data wire (such as D+ and/orD− wire) of the USB interface. For another example, the charginginterface 223 may be the USB interface supporting a PD (power delivery)communication protocol, and the communication control circuit 222 maycommunicate with the power supply device 210 based on the PDcommunication protocol.

In embodiments of the present disclosure, the manner in which the powersupply device 210 adjusts the output power is not specifically limited.For example, the power supply device 210 can be internally provided witha voltage feedback loop and a current feedback loop to enable adjustmentof its output voltage and/or output current according to practicalrequirements.

FIG. 5 is another example of a method of adjusting the transmittingpower of the wireless transmitting circuit 221 according to anembodiment of the present disclosure. Different from FIG. 4, theembodiment illustrated in FIG. 5 is not intended to control the maximumoutput power of the power supply device 210, but to relativelyaccurately control the output power of the power supply device 210, soas to make the output power of the power supply device 210 directly meetthe present power requirements. Moreover, in contrast to the embodimentin FIG. 4, in the embodiment as illustrated in FIG. 5, adjusting thetransmitting power of the wireless transmitting circuit 221 iscontrolled by the power supply device, which adjusts the transmittingpower of the wireless transmitting circuit 221 by changing the outputvoltage and/or the output current. This way of adjusting thetransmitting power is advantageous in that, the power supply device 210may provide as much power as the wireless charging device 220 needs,thus avoiding waste of power. In the following, detailed description isprovided with reference to FIG. 5.

As illustrated in FIG. 5, the wireless charging device 220 provided byembodiments of the present disclosure may further include a charginginterface 223 and a voltage conversion circuit 224. The charginginterface 223 may be configured to be coupled to the power supply device210. The voltage conversion circuit 224 may be configured to receive anoutput voltage of the power supply device 210 and convert the outputvoltage of the power supply device 210 to obtain an output voltage andan output current of the voltage conversion circuit 224. The wirelesstransmitting circuit 221 may be further configured to generate theelectromagnetic signal according to the output voltage and the outputcurrent of the voltage conversion circuit 224. The communication controlcircuit 222 may be further configured to communicate with the powersupply device 210 to negotiate the output voltage and/or output currentof the power supply device 210.

In embodiments of the present disclosure, the energy transmission isperformed by using a high-voltage low-current method. This energytransmission mode requires a high input voltage (for example, 10V or20V) of the wireless transmitting circuit 221, and if the maximum outputvoltage of the power supply device 210 cannot reach the input voltagerequirement of the wireless transmitting circuit 221, the setting of thevoltage conversion circuit 224 may make it impossible for the inputvoltage of the wireless transmitting circuit 221 to reach a desiredinput voltage. Of course, in some embodiments, if the output voltage ofthe power supply device 210 can reach the input voltage requirement ofthe wireless transmitting circuit 221, the voltage conversion circuit224 can also be omitted to simplify the implementation of the wirelesscharging device 220.

The voltage conversion circuit 224 may be a voltage boosting circuit.The boosting factor of the voltage conversion circuit 224 and thestep-down factor of the step-down circuit 234 are related to parameterssuch as the output voltage that can be provided by the power supplydevice 210, and the charging voltage required by the battery 232. Theboosting factor and the step-down factor may be equal or non-equal,which are not specifically limited in this embodiment of the presentdisclosure. As an implementation, the boosting factor of the voltageconversion circuit 224 and the step-down factor of the step-down circuit234 may be set equal. For example, the voltage conversion circuit 224may be a voltage doubling circuit for boosting the output voltage of thepower supply device 210 by a factor of two; the step-down circuit 234may be a half voltage circuit for reducing the output voltage of thewireless receiving circuit 231 by half.

In embodiments of the present disclosure, the boosting factor of thevoltage conversion circuit 224 and the step-down factor of the step-downcircuit 234 is set to 1:1. This arrangement can make the output voltageand the output current of the step-down circuit 234 consistent withthose of the power supply device 210 respectively, which facilitatessimplifying the implementation of the communication control circuits222, 236. Taking the requirement of the charging current of the battery232 being 5 A as an example, when the communication control circuit 236learns that the output current of the step-down circuit 234 is 4.5 A, itis necessary to adjust the output power of the power supply device 210,so that the output current of the step-down circuit 234 reaches 5 A. Ifthe ratio of the boosting factor of the voltage conversion circuit 224and the step-down factor of the step-down circuit 234 is not equal to1:1, the communication control circuit 222 or the communication controlcircuit 236, when adjusting the output power of the power supply device210, needs to recalculate the adjustment value of the output power ofthe power supply device 210 based on the difference between the presentoutput current of the step-down circuit 234 and the expected value. Inembodiments of the present disclosure, the ratio of the boosting factorof the voltage conversion circuit 224 and the step-down factor of thestep-down circuit 234 is set to 1:1, and the communication controlcircuit 236 notifies the communication control circuit 222 to increasethe output current to 5 A, which simplifies the feedback adjustmentmanner of the wireless charging channel.

In the embodiment as illustrated in FIG. 5, the wireless charging device220 may take the initiative to determine whether there is a need toadjust the output voltage and/or the output current of the power supplydevice. In other embodiments, the wireless charging device 220 may actas a bridge for communication between the power supply device 210 andthe device to be charged 230, and is mainly responsible for forwardinginformation between the two.

For example, during the wireless charging, the communication controlcircuit 222 communicates with the device to be charged 230, to determinewhether there is a need to adjust the output voltage and/or the outputcurrent of the power supply device 210. When there is a need to adjustthe output voltage and/or the output current of the power supply device210, the communication control circuit 222 communicates with the powersupply device 210 to instruct the power supply device 210 to adjust theoutput voltage and/or the output current of the power supply device 210.

For another example, during the wireless charging, the communicationcontrol circuit 222 in the wireless charging device 220 performswireless communication with the device to be charged 230 to obtain anadjustment message, in which the adjustment message is configured toinstruct adjusting the output voltage and/or the output current of thepower supply device 210. The communication control circuit 222communicates with the power supply device 210 to send the adjustmentmessage to the power supply device 210, such that the power supplydevice 210 adjusts the output voltage and/or the output current of thepower supply device according to the adjustment message.

It should be understood that, similar to the communication mode betweenthe wireless charging device 220 and the device to be charged 230, thecommunication between the wireless charging device (or the communicationcontrol circuit 222) and the power supply device 210 may be theunidirectional communication, or may be the bidirectional communication,which is not limited in embodiments of the present disclosure.

It should also be understood that, the output current of the powersupply device may be constant direct current, pulsating direct currentor alternating current, which is not limited in embodiments of thepresent disclosure.

In the embodiment as illustrated in FIG. 5, the communication controlcircuit 222 may be coupled to the wireless transmitting circuit 221, sothat the wireless transmitting circuit 221 may be controlled to startworking, or the wireless transmitting circuit 221 may be controlled tostop working when the wireless charging process is abnormal. In someembodiments, the communication control circuit 222 may not be coupled tothe wireless transmitting circuit 221.

FIG. 6 is another example of the transmitting power adjustment manner ofthe wireless transmitting circuit 221. Different from the embodimentsillustrated in FIGS. 4 and 5, the wireless charging device 220corresponding to the embodiment of FIG. 6 does not acquire electricenergy from the power supply device 210, but directly converts thealternating current input from the external (such as the mains supply)into the electromagnetic signal.

As illustrated in FIG. 6, the wireless charging device 220 may furtherinclude a voltage conversion circuit 224 and a power supply circuit 225.The power supply circuit 225 may be configured to receive thealternating current input from the external (such as the mains supply)and generate an output voltage and an output current of the power supplycircuit 225 according to the alternating current. For example, the powersupply circuit 225 may perform rectification and/or filtering on thealternating current to obtain direct current or pulsating direct currentand transmit the direct current or the pulsating direct current to thevoltage conversion circuit 224.

The voltage conversion circuit 224 may be configured to receive theoutput voltage of the power supply circuit 225 and convert the outputvoltage of the power supply circuit 225 to obtain the output voltage andoutput current of the voltage conversion circuit 224. The wirelesstransmitting circuit 221 may be further configured to generate theelectromagnetic signal according to the output voltage and the outputcurrent of the voltage conversion circuit 224.

In embodiments of the present disclosure, the function similar to theadapter is integrated in the wireless charging device 220, such that thewireless charging device 220 does not need to obtain power from theexternal power supply device, which improves the integration level ofthe wireless charging device 220, and reduces the number of elementsrequired for the wireless charging.

In embodiments of the present disclosure, the energy transmission isperformed by using a high-voltage low-current method. This energytransmission mode requires a high input voltage (for example, 10V or20V) of the wireless transmitting circuit 221, and if the maximum outputvoltage of the power supply circuit 225 cannot reach the input voltagerequirement of the wireless transmitting circuit 221, the setting ofvoltage conversion circuit 224 may make it impossible for the inputvoltage of wireless transmitting circuit 221 to reach the desired inputvoltage. Of course, in some embodiments, if the output voltage of thepower supply circuit 225 can reach the input voltage requirement of thewireless transmitting circuit 221, the voltage conversion circuit 224can also be omitted to simplify the implementation of the wirelesscharging device 220.

In some embodiments, the wireless charging device 220 may support afirst wireless charging mode and a second wireless charging mode, inwhich a charging speed of the wireless charging device 220 charging thedevice to be charged 230 in the first wireless charging mode is greaterthan a charging speed of the wireless charging device 220 charging thedevice to be charged 230 in the second wireless charging mode. In otherwords, compared to the wireless charging device 220 working in thesecond wireless charging mode, the wireless charging device 220 workingin the first wireless charging mode can fully charge the battery havingthe same capacity in the device to be charged 230 in a shorter timeperiod.

The second wireless charging mode may be referred to as a normalwireless charging mode, which may be, for example, the conventionalwireless charging mode based on QI standard, PMA standard or A4WPstandard. The first wireless charging mode may be referred to as a fastwireless charging mode. The normal wireless charging mode may refer tothe wireless charging mode in which the transmitting power of thewireless charging device 220 is relatively lower (typically, less than15 W, and the commonly used transmitting power is 5 W or 10 W). In thenormal wireless charging mode, it may take several hours to fully chargea larger capacity battery (such as a battery with 3000 mAh). Incontrast, under the fast wireless charging mode, the transmitting powerof the wireless charging device 220 is relatively higher (typically,greater than or equal to 15 W). Compared to the normal wireless chargingmode, the charging speed of the wireless charging device 220 in the fastwireless charging mode is faster, and the charging time required forfully charging a battery with a same capacity in the fast wirelesscharging mode may be significantly shortened.

In some embodiments, the communication control circuit 222 performs thebidirectional communication with the communication control circuit 236,to control the transmitting power of the wireless charging device 220 inthe first wireless charging mode.

Further, in some embodiments, the communication control circuit 222 mayperform the bidirectional communication with the communication controlcircuit 236 to control the transmitting power of the wireless chargingdevice 220 in the first wireless charging mode as follows. Thecommunication control circuit 222 performs the bidirectionalcommunication with the communication control circuit 236 to negotiatethe wireless charging mode between the wireless charging device 220 andthe device to be charged 230.

In detail, the communication control circuit 222 may perform handshakecommunication with the communication control circuit 236, control thewireless charging device 220 to charge the device to be charged 230 inthe first wireless charging mode when the handshake communicationsucceeds, and control the wireless charging device 220 to charge thedevice to be charged 230 in the second wireless charging mode when thehandshake communication fails.

The handshake communication may refer to recognize the other's identityby any of the communication parties. When the handshake communicationsucceeds, it indicates that both the wireless charging device 220 andthe device to be charged 230 support the wireless charging mode withadjustable transmitting power provided by embodiments of the presentdisclosure. When the handshake communication fails, it indicates that atleast one of the wireless charging device 220 and the device to becharged 230 does not support the wireless charging mode with adjustabletransmitting power provided by embodiments of the present disclosure.

In embodiments of the present disclosure, the wireless charging device220 does not perform the fast wireless charging on the device to becharged 230 in the first wireless charging mode blindly, but performsthe bidirectional communication with the device to be charged 230 tonegotiate whether the wireless charging device 220 can perform the fastwireless charging on the device to be charged 230 in the first wirelesscharging mode. In this way, safety of charging process can be improved.

In detail, the communication control circuit 222 performs thebidirectional communication with the communication control circuit 236to negotiate the wireless charging mode between the wireless chargingdevice 220 and the device to be charged 230 as follows. Thecommunication control circuit 222 sends a first instruction to thecommunication control circuit 236, in which the first instruction isconfigured to query the device to be charged 230 whether to operate inthe first wireless charging mode. The communication control circuit 222receives a reply instruction of the first instruction sent by thecommunication control circuit 236, in which the reply instruction of thefirst instruction is configured to indicate whether the device to becharged 230 agrees to operate in the first wireless charging mode. Whenthe device to be charged 230 agrees to operate in the first wirelesscharging mode, the communication control circuit 222 controls thewireless charging device 220 to charge the device to be charged 230 inthe first wireless charging mode.

Besides determining the wireless charging mode based on the negotiation,the communication control circuit 222 may select or switch the wirelesscharging mode according to some other factors. For example, thecommunication control circuit 222 may control the wireless chargingdevice 220 to charge the battery 232 in the first wireless charging modeor in the second wireless charging mode according to the temperature ofthe battery 232.

For example, when the temperature is less than a preset threshold (forexample, 5° C. or 10° C.) set in advance, the communication controlcircuit 222 may control the wireless charging device 220 to perform thenormal charging in the second wireless charging mode; when thetemperature is greater than or equal to the first threshold, thecommunication control circuit 222 may control the wireless chargingdevice 220 to perform the fast charging in the first wireless chargingmode. Further, when the temperature is greater than a high temperaturethreshold (for example, 50° C.), the communication control circuit 222may control the wireless charging device 220 to stop charging.

It should be noted that, the wireless charging mode with adjustabletransmitting power provided by embodiments of the present disclosure maybe used to control one or more of charging stages of the battery 232.For example, the wireless charging mode with adjustable transmittingpower provided by embodiments of the present disclosure may be mainlyused to control the constant current charging stage of the battery 232.In other embodiments, the device to be charged 230 may keep theconversion circuit. When the battery is in the trickle charging stageand the constant voltage charging stage, the conventional wirelesscharging mode as illustrated in FIG. 1 is used for charging. In detail,when the battery 232 is in the trickle charging stage and the constantvoltage charging stage, the conversion circuit in the device to becharged 230 may convert the output voltage and the output current of thewireless receiving circuit 231, to make them satisfy the chargingrequirement of the trickle charging stage and the constant voltagecharging stage. Compared to the constant current charging stage, thecharging power received by the battery 232 in the trickle charging stageand the constant voltage charging stage is lower, and efficiency lossand heat accumulation of the conversion circuit in the device to becharged 230 are acceptable. Detailed description will be given belowwith reference to FIG. 7.

As illustrated in FIG. 7, the charging channel where the step-downcircuit 234 is located may be referred to as a first charging channel233. The device to be charged 230 may further include a second chargingchannel 239. The conversion circuit 237 may be arranged on the secondcharging channel 239. The conversion circuit 237 may be configured toreceive the output voltage and the output current of the wirelessreceiving circuit 231, to perform constant voltage and/or constantcurrent control on the output voltage and/or the output current of thewireless receiving circuit 231, such that the output voltage and/or theoutput current of the second charging channel 239 match the chargingvoltage and/or the charging current presently required by the battery232, and the battery 232 is charged based on the output voltage and/orthe output current of the second charging channel 239. The communicationcontrol circuit 236 may be further configured to control switch betweenthe first charging channel 233 and the second charging channel 239. Forexample, as illustrated in FIG. 7, the first charging channel 233 may beprovided with a switch 238, and the communication control circuit 236may control the switch between the first charging channel 233 and thesecond charging channel 239 by controlling the switch 238 to switch onand off. As described above, in some embodiments, the wireless chargingdevice 220 may include a first wireless charging mode and a secondwireless charging mode, in which a charging speed of the wirelesscharging device 220 charging the device to be charged 230 in the firstwireless charging mode is greater than a charging speed of the wirelesscharging device 220 charging the device to be charged 230 in the secondwireless charging mode. When the wireless charging device 220 chargesthe battery in the device to be charged 230 in the first wirelesscharging mode, the device to be charged 220 may control the firstcharging channel 233 to work. When the wireless charging device 220charges the battery in the device to be charged 230 in the secondwireless charging mode, the device to be charged 230 may control thesecond charging channel 239 to work.

For example, when the battery 232 is in the trickle charging stageand/or the constant voltage charging stage, the communication controlcircuit 236 may control charging the battery 232 in the second chargingchannel 239, in which the constant voltage and constant current processof the battery may be controlled by the conversion circuit 237 (forexample, a charging IC). When the battery 232 is in the constant currentcharging stage, the communication control circuit 236 may controlcharging the battery 232 in the first charging channel 233, in which theconstant current control of the battery may be implemented based onadjusting the transmitting power by the wireless charging device.Keeping the conversion circuit 237 makes it to be compatible with theconventional wireless charging mode better.

It should be noted that, there are various ways for selecting betweenthe first charging channel 233 and the second charging channel 239,which is not limited to select based on the charging stage where thebattery 232 is presently is.

In some embodiments, the communication control circuit 236 may beconfigured to perform handshake communication with the communicationcontrol circuit 222, to control the first charging channel 233 to workwhen the handshake communication succeeds, and to control the secondcharging channel 239 to work when the handshake communication fails.

The handshake communication may refer to recognize the other's identityby any of the communication parties. When the handshake communicationsucceeds, it indicates that both the wireless charging device 220 andthe device to be charged 230 support the wireless charging mode withadjustable transmitting power provided by embodiments of the presentdisclosure. When the handshake communication fails, it indicates that atleast one of the wireless charging device 220 and the device to becharged 230 does not support the wireless charging mode with adjustabletransmitting power provided by embodiments of the present disclosure. Ina case that the handshake communication fails, the charging may beperformed via the second charging channel 239 and the conventionalwireless charging mode, such as the wireless charging mode based on QIstandard may be adopted.

In other embodiments, the communication control circuit 236 may befurther configured to control the switch between the first chargingchannel 233 and the second charging channel 239 according to thetemperature of the battery 232.

For example, when the temperature is less than a preset threshold (forexample, 5° Cor10° C.) set in advance, the communication control circuit236 may control performing the normal wireless charging via the secondcharging channel 239; when the temperature is greater than or equal tothe first threshold, the communication control circuit 236 may controlperforming the fast wireless charging via the first charging channel233. Further, when the temperature is greater than a high temperaturethreshold (for example, 50° C.), the communication control circuit 236may control stopping the wireless charging.

As noted above, the output current of the wireless receiving circuit 231may be pulsating direct current, which may reduce the lithiumprecipitation of the battery 232, and improve the service life of thebattery. When the wireless receiving circuit 231 outputs the pulsatingdirect current, the peak value or the mean value of the pulsating directcurrent may be detected by the detection circuit 234, such that thecommunication control circuit 236 may perform subsequent communicationor control based on the peak value or mean value of the pulsating directcurrent.

In some embodiments, the wireless charging device 220 may furtherinclude a peripheral interface and a wireless data transmission circuit.The peripheral interface may be configured to be coupled with anelectronic device having functions of data processing and transmission.The peripheral interface may be the charging interface described above,or may be other interfaces. The communication control circuit 222 may befurther configured to perform the wireless charging on the device to becharged 230 according to the output power of the electronic device whenthe peripheral interface is coupled with the electronic device havingfunctions of data processing and transmission. The wireless datatransmission circuit may be configured to transmit data stored in theelectronic device to the device to be charged 230 via a wireless link,or transmit data stored in the device to be charged 230 to theelectronic device, during the process in which the wireless chargingcontrol unit performs the wireless charging on the device to be charged230 according to the output power of the electronic device. The wirelessdata transmission circuit may be configured to transmit at least one ofdata in a USB protocol format, data in a DP (display port) protocolformat, and data in a MHL (mobile high-definition link) format.

Hereinbefore, device embodiments of the present disclosure are describedin detail with reference to FIGS. 2-7. Hereinafter, method embodimentsof the present disclosure will be described in detail with reference toFIGS. 8-9. The method embodiments are corresponding to the deviceembodiments, and thus with respect to parts that are not described indetail, reference may be made to above device embodiments.

FIG. 8 is a schematic flowchart of a charging control method accordingto an embodiment of the present disclosure. The method may be applied toa device to be charged.

The method in FIG. 8 includes following blocks 810-840.

At block 810, an electromagnetic signal is received and converted to afirst output voltage.

At block 820, a step-down process is performed on the first outputvoltage to generate a second output voltage, and a battery of the deviceto be charged is charged based on the second output voltage.

At block 830, a temperature of the device to be charged is detected.

At block 840, when the temperature of the device to be charged isgreater than a preset threshold, feedback information is sent to thewireless charging device, in which the feedback information isconfigured to trigger the wireless charging device to control thewireless charging process, to reduce the first output voltage.

In some embodiments, the method in FIG. 8 may further include:performing wireless communication with the wireless charging device,such that the wireless charging device controls the wireless chargingprocess, to enable the second output voltage and/or an output currentcorresponding to the second output voltage to match a charging voltageand/or a charging current presently required by the battery.

FIG. 9 is a schematic flowchart of a charging control method accordingto another embodiment of the present disclosure. The method may beapplied to a wireless charging device.

The method in FIG. 9 includes blocks 910-930.

At block 910, an electromagnetic signal is transmitted to performwireless charging on a device to be charged.

At block 920, feedback information is received, in which the feedbackinformation is sent by the device to be charged when a temperature ofthe device to be charged is greater than a preset threshold.

At block 930, the wireless charging is controlled according to thefeedback information, to reduce an output voltage of a wirelessreceiving circuit of the device to be charged.

In some embodiments, block 930 may include: reducing a duty ratio oftransmitting the electromagnetic signal according to the feedbackinformation, to reduce the output voltage of the wireless receivingcircuit.

In some embodiments, block 930 may include: adjusting a transmittingfrequency of transmitting the electromagnetic signal according to thefeedback information, to reduce the output voltage of the wirelessreceiving circuit.

In some embodiments, the method may further include boosting an inputvoltage of the wireless charging device to obtain a boosted voltage, andgenerating the electromagnetic signal according to the boosted voltage,and block 930 may include reducing the boosted voltage, to reduce theoutput voltage of the wireless receiving circuit.

In some embodiments, the method in FIG. 9 may further include:performing wireless communication with the device to be charged, toadjust a transmitting power of transmitting the electromagnetic signal,such that the transmitting power of transmitting the electromagneticsignal matches a charging voltage and/or a charging current presentlyrequired by a battery of the device to be charged.

In above embodiments, it is possible to implement the embodiments fullyor partially by software, hardware, firmware or any other combination.When implemented by software, it is possible to implement theembodiments fully or partially in a form of computer program products.The computer program product includes one or more computer instructions.When the computer program instructions are loaded and executed by thecomputer, procedures or functions according to embodiments of thepresent disclosure are fully or partially generated. The computer may bea general-purpose computer, a special-purpose computer, a computernetwork, or any other programmable device. The computer instructions maybe stored in a computer readable storage medium, or may be transmittedfrom one computer readable storage medium to another computer readablestorage medium. For example, the computer instructions may betransmitted from one website, computer, server or data center to anotherwebsite, computer, server or data center in a wired manner (for example,via coaxial cables, fiber optics, or DSL (digital subscriber line)) orin a wireless manner (for example, via infrared, WiFi or microwave). Thecomputer readable storage medium may be any available medium that areaccessible by the computer, or a data storage device such as a server ora data center integrated with one or more available medium. Theavailable medium may be magnetic medium (for example, floppy disk, harddisk and tape), optical medium (for example, DVD (digital video disc)),or semiconductor medium (for example, SSD (solid state disk)).

Those skilled in the art could be aware that, example units andalgorithm steps described in combination with embodiments disclosedherein may be implemented by electronic hardware, or by a combination ofcomputer software and electronic hardware. Whether these functions areexecuted by hardware or software is dependent on particular use anddesign constraints of the technical solutions. Professionals may adoptdifferent methods for different particular use to implement describedfunctions, which should not be regarded as going beyond the scope of thepresent disclosure.

In several embodiments provided by the present disclosure, it should beunderstood that, the disclosed system, device and method may beimplemented in other ways. For example, the device embodiments describedabove are merely illustrative. For example, the units are merely dividedaccording to logic functions, and can be divided in other ways in actualimplementation. For example, a plurality of units or components may becombined or may be integrated into another system, or some features maybe ignored or not executed. In addition, the mutual coupling or directcoupling or communication connection illustrated or discussed may be viasome interfaces, or direct coupling or communication connection ofdevices or units may be in an electrical, mechanical, or other form.

The devices and apparatus mentioned in the present disclosure may eachbe a chip system or a device or an apparatus having a housing.

The units described as separate components may or may not be physicallyseparated, and the components displayed as units may or may not bephysical units, that is, may be located at one place, or may bedistributed to multiple network units. Some or all of the units may beselected according to practical requirements to achieve the purpose ofthe solution of the embodiment.

Moreover, respective functional units in respective embodiments of thepresent disclosure may be integrated in one processing unit, or therespective units may be separate physical existence, or two or moreunits may be integrated in one unit.

Above description is merely specific implementation of the presentdisclosure. However, the protection scope of the present disclosure isnot limited to this. Any change or substitute that is conceivable bythose skilled in the art should be in the protection scope of thepresent disclosure. Thus, the protection scope of the present disclosureshould be defined as the protection scope of claims.

What is claimed is:
 1. A device to be charged, comprising: a wirelessreceiving circuit, configured to receive an electromagnetic signaltransmitted by a wireless charging device and convert theelectromagnetic signal to an output voltage of the wireless receivingcircuit; a step-down circuit, configured to receive the output voltageof the wireless receiving circuit, perform step-down process on theoutput voltage of the wireless receiving circuit to obtain an outputvoltage of the step-down circuit, and charge a battery of the device tobe charged based on the output voltage of the step-down circuit; atemperature detecting circuit, configured to detect a temperature of thedevice to be charged; and a communication control circuit, configured tosend feedback information to the wireless charging device, when thetemperature of the device to be charged is larger than a presetthreshold, wherein the feedback information is configured to trigger thewireless charging device to control wireless charging process to reducethe output voltage of the wireless receiving circuit.
 2. The device tobe charged according to claim 1, wherein the communication controlcircuit is further configured to perform wireless communication with thewireless charging device, such that the wireless charging devicecontrols the wireless charging process to enable at least one of theoutput voltage or an output current of the step-down circuit to match atleast one of a charging voltage or a charging current presently requiredby the battery.
 3. The device to be charged according to claim 1,wherein the step-down circuit is a BUCK circuit.
 4. The device to becharged according to claim 1, wherein the temperature detecting circuitcomprises a temperature detecting resistor.
 5. The device to be chargedaccording to claim 4, wherein the temperature detecting resistor isintegrated in the same chip with the step-down circuit.
 6. A wirelesscharging device, comprising: a wireless transmitting circuit, configuredto transmit an electromagnetic signal to perform wireless charging on adevice to be charged; and a communication control circuit, configuredto: receive feedback information sent by the device to be charged when atemperature of the device to be charged is greater than a presetthreshold; and control the wireless charging according to the feedbackinformation to reduce an output voltage of a wireless receiving circuitof the device to be charged.
 7. The wireless charging device accordingto claim 6, wherein the communication control circuit is configured to:reduce a duty ratio of the wireless transmitting circuit according tothe feedback information, to reduce the output voltage of the wirelessreceiving circuit.
 8. The wireless charging device according to claim 6,wherein the communication control circuit is configured to: adjust atransmitting frequency of the wireless transmitting circuit according tothe feedback information, to reduce the output voltage of the wirelessreceiving circuit.
 9. The wireless charging device according to claim 6,further comprises: a voltage conversion circuit, configured to boost aninput voltage of the wireless charging device to obtain an outputvoltage and an output current of the voltage conversion circuit;wherein, the wireless transmitting circuit is configured to generate theelectromagnetic signal according to the output voltage and the outputcurrent of the voltage conversion circuit; and wherein, thecommunication control circuit is configured to: reduce the outputvoltage of the voltage conversion circuit according to the feedbackinformation, to reduce the output voltage of the wireless receivingcircuit.
 10. The wireless charging device according to claim 6, whereinthe communication control circuit is further configured to performwireless communication with the device to be charged to adjust atransmitting power of the wireless transmitting circuit, such that thetransmitting power of the wireless transmitting circuit matches at leastone of a charging voltage or a charging current presently required by abattery of the device to be charged.
 11. The wireless charging deviceaccording to claim 9, wherein the voltage conversion circuit is avoltage boosting circuit.
 12. The wireless charging device according toclaim 11, wherein a boosting factor of the voltage boosting circuit isequal to a step-down factor of reducing the output voltage of thewireless receiving circuit.
 13. A method for charging control, appliedto a wireless charging device, and the method comprising: transmittingan electromagnetic signal to perform wireless charging on a device to becharged; receiving feedback information sent by the device to be chargedwhen a temperature of the device to be charged is greater than a presetthreshold; and controlling the wireless charging according to thefeedback information to reduce an output voltage of a wireless receivingcircuit of the device to be charged.
 14. The method according to claim13, wherein controlling the wireless charging according to the feedbackinformation to reduce the output voltage of the wireless receivingcircuit of the device to be charged, comprises: reducing a duty ratio oftransmitting the electromagnetic signal according to the feedbackinformation, to reduce the output voltage of the wireless receivingcircuit.
 15. The method according to claim 13, wherein controlling thewireless charging according to the feedback information to reduce theoutput voltage of the wireless receiving circuit of the device to becharged, comprises: adjusting a transmitting frequency of transmittingthe electromagnetic signal according to the feedback information, toreduce the output voltage of the wireless receiving circuit.
 16. Themethod according to claim 13, further comprising: boosting an inputvoltage of the wireless charging device to obtain a boosted voltage; andgenerating the electromagnetic signal according to the boosted voltage,wherein, controlling the wireless charging according to the feedbackinformation to reduce the output voltage of the wireless receivingcircuit of the device to be charged, comprises: reducing the boostedvoltage according to the feedback information, to reduce the outputvoltage of the wireless receiving circuit.
 17. The method according toclaim 13, further comprising: performing wireless communication with thedevice to be charged, to adjust a transmitting power of transmitting theelectromagnetic signal, such that the transmitting power of transmittingthe electromagnetic signal matches at least one of a charging voltage ora charging current presently required by a battery of the device to becharged.